=vasovagal syncope, faints, “whitey”.  Insufficient blood to the brain, due to immature or hyporesponsive autonomic nervous system control of cardiac output and peripheral vascular tone.

Similar symptoms with POTS but without obvious drop in blood pressure.

Typically fast growing teenagers, but can be anyone.  In some, lifelong tendency.  You can suffer significant facial trauma from syncope so it’s not trivial, if recurrent can also be significant psychological co-morbidity.

First thing is recognition of impending faint (“presyncope”): feeling hot, black spots in vision, tunnel vision, etc.  Usually provoked by standing up after sitting/lying for a while.  Other common triggers are painful procedures, esp immunisation, cannulation.  Some unusual triggers eg hair brushing/combing.

Collapse should be brief, as being supine will restore blood supply to brain.  1-2 minutes maximum.  A hypoxic seizure can be triggered –  typically posturing rather than tonic clonic, again, brief (seconds only).

Useful to become aware of triggers, so countermeasures can be tried.  But sometimes no warning, which is difficult.  Worth asking directly how often symptoms happen, as child might not tell anyone.

Assuming normal physical examination, and no exercise related features (else consider cardiomyopathy with arrhythmia), aim for at least 2 litres (6 glasses) fluid intake daily, adequate salt (only usually a problem in people trying to be super healthy or losing a lot in sport), regular meals and snacks, good cardiovascular fitness.

Could try putting blocks under the foot of the bed to raise it up 2-3 inches!

Desmopressin, to increase circulating blood volume?

Countermeasures

• Lower body muscle tensing – abdomen, buttocks, thighs
• Same, but with leg crossing
• Whole body tensing!
• Squatting
• “Brace” position – sit with head between knees

These should all work, probably worth practicing though.  And should work within seconds.  You hopefully only need to keep doing it for 30-60 seconds. [Krediet, J Appl Physiology 2005 Vol. 99 no. 5, 1697-1703 DOI: 10.1152/japplphysiol.01250.2004]  All of the evidence seems to come from the Netherlands!  Some evidence for isometric arm/hand exercises, but might be incidental abdominal tensing at same time!

Cognitive behavioural therapy makes sense, if the trigger is a situation (eg attending hospital), rather than an actual physical stimulus.

See STARS for patient support.